Who needs a tank, just solo him!
I guess every ranged class is capable of solo'ing it. Solo'ing it is one of the most nervebreaking tasks I've ever done. It took me exactly 40 minutes to down it, carefully swimming in the right space, hoping you don't swim into another Whale Shark (there are at least 3 of these beast splashing about)

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Try 1: it goes fine, a bit unsure about what will happen, but everything goes well.
After 5 minutes (8750k health left), you look behind you and you see a big fish going your way. Another Whale Shark! Quickle adjusting your path so you don't hit him, you make a sharp turn and you get into range of the former one. Receiving a 'normal' hit of 700k makes quick work of your hopes.

Second try:
The start is fine, and you were able to avoid the second whale as well, without getting yourself one-shotted. Having the whale at 40% after 22 minutes, you notice that you have been swimming downwards for a long time, and you want to get yourself back to a nice level. Swimming up, you see the whale closing, the meters dropping fast! The moment the rangedisplay says 8 yards you almost pissed your pants and you turn around trying to swim toward the 20 yards range, but you cross it. Result: you see the whale bobbing around aimlessly, evading all your attacks.

But you are not giing up yet!

Try 3:
Pulled wrong, getting hit by 1,5 mil.

Try 4:
Wrong spot to pull, after 5 minutes you enter the fatigue-zone, and while trying to leave it you reset it.

Try 5:
Frustrated and tired (it has been 2 hours since you started) you give it one more shot, not willing to give in. Carefully moving around, avoiding everything that might or might not interupt your travels, you feel confident.
20 minutes you've been swimming this time, and you feel your fingers getting stiff, partly because of being tired, but also because of the constant backswim. Still managing your way around, you get him to 24%. Your hands are getting sweaty, you need to go to the bathroom and the dog is chewing on your feet, but you keep going!
At 10%, sweat is pouring out of your body, making your keyboard look like it has been put in a bucket of water, your feets are bleeding and the dog is chewing on something what seems to be one of your big toes.
At 1% you've lost every sence of your surroundings, the only thing in your mind is that awefully big mouth at wich you've been starring for the past 39 minutes. Not even looking at rangedisplay anymore, you instinctivily move backwards, while getting the last bits from his health.

Guildmembers are yelling why you don't react, angry wishpers ending with /ignore are popping up like there is no end to it and your parents are trying to break your keyboard free from your grasp when suddenly you see the Big White Guy tip over. An Achievement pops up, and it seems you did it. Even though you can't see clearly, are now socially expelled, missing one-and-a-half-foot, your keyboard is dripping stuff off wich you didn't know it existed, you did it.

Now go to sleep!

Almost word for word exactly what I did.

Soloed for ~40 minutes (3 hours counting all pulls) on a level 80 mage, kited through all 3 zones.

Very informative guide, one thing though that's still unclear for me. Does the Whale Shark have a big hitbox (think i saw 20 yards mentioned somewhere)? This would be important because:
1. It means melee can solo him as well
2. Tanks can actually build threat on it (group tactic, not solo).

A friend of mine (Shadow priest) tanked him while I (Ret Paladin) used cd's and then salved myself and slowed dmg. Ideal setup? No way but it only took us 9 minutes.
We then decided another day to do it again. He on his Boomkin and me on my mage. It took about 7 1/2-8 minutes. I was arcane which was nice for threat drops but I think fire would be better for scorch spamming.

Addons used : None
Deaths : 1x because I pulled threat on my mage like a tard :P

Note : His hitbox is retarted and like towards the middle of his body, and he is very glitchy when he moves or gets near objects so clear a path and gl

Just did it as a hunter, for some reason my pet got killed in between by a fear/hit (as MM) but kept going in fox, overall 7k dps while chatting on vent Kept within 15-20-30 and it was fine. Just kept going in circles.